Nonaqueous electrolyte battery is attracting great attention as medium-sized or large-sized power source for hybrid car or electric car. Such an application demands long life and high safety of the nonaqueous electrolyte battery.
As the positive electrode active material used in the nonaqueous electrolyte battery, lithium-transition metal complex oxide containing Co, Mn, or Ni, lithium-transition metal complex oxide having a layer structure such as lithium cobaltate, and lithium-transition metal oxide having a spinel structure such as lithium manganate have been developed.
As the negative electrode active material used in the nonaqueous electrolyte battery, a carbonaceous material is generally used. Recently, however, materials in which insertion and release of lithium ions occur at higher potentials have been developed. Among the materials, a lithium titanate and a titanium complex oxide which have a spinel structure are expected to have high safety.